Lakes / Colorado / Weld County / Foster Reservoir
Foster Reservoir, Colorado
137 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Colorado
40.19 degrees N, 104.99 degrees W - Weld County. State and county outlines drawn from Census boundary data; the lake marker is placed by its USGS National Hydrography Dataset coordinates, not by eye. Schematic - not a survey map.
How Foster Reservoir Stacks Up
- Larger than 73% of the 778 lakes counted in Colorado.
- About 19 miles from Boulder, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Highland Reservoir Number 3 | Weld | 0.1 mi | 34 acres |
| Sanborn Reservoir | Weld | 0.7 mi | 35 acres |
| Mulligan Reservoir | Weld | 1.2 mi | 84 acres |
| Lake Thomas | Weld | 2.8 mi | 175 acres |
| Calkins Lake | Weld | 2.8 mi | 749 acres |
| Highland Lake | Weld | 3.9 mi | 47 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Foster Reservoir
How Big Is Foster Reservoir?
Foster Reservoir covers 137 acres in Weld County, Colorado.
What Is the Largest Lake in Weld County?
Riverside Reservoir is the largest lake in Weld County, at 3,633 acres.
Largest Lakes in Colorado
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | John Martin Reservoir | Bent | 11,686 acres | - |
| 2 | Blue Mesa Reservoir | Gunnison | 8,944 acres | - |
| 3 | Lake Granby | Grand | 7,075 acres | - |
| 4 | Lake Meredith | Crowley | 5,539 acres | - |
| 5 | Adobe Creek Reservoir | Bent | 4,770 acres | - |
All 778 Colorado lakes ranked by surface area
Sources: USGS NHD (The National Map NHD MapServer layer 12) named waterbodies FTYPE 390/436; counties via Census point-in-polygon lake data (ID 128057822). Verified October 30, 2026.